Gillian and Neil struggle with the exact same disease challenges on their farm as any other. In fact, the OAD system ups the ante in terms of keeping herd SCC at low levels, as both acknowledge.

"In 2013 we realised that we had a problem. It wasn't that we got a milk test back one morning and it hit us - it was much more insidious than that," explains Gillian.

"The SCC had reached 175,000, and every time we recorded, we'd find that we had another cow with a cell-count over 250,000.

"We started testing, which in itself is a frustrating process because it can take over a week to get results back from the processor's lab. But we discovered that we had a Staph Aureus infection in the herd.

"It probably started in 2011 with one cow, but it spread to 60pc of the heifers by the time we started to tackle it in earnest in 2013. Milk recording allowed us to identify the problem cows and monitor any new infections. But the disease has a really low cure rate, even though we were using long-acting antibiotics during the dry period, so we have had to cull out those problem cows.

"We also switched to a pre-dipping and drying routine, along with post-dipping both the teats and the clusters.

"This obviously slows down milking, but it also required us to switch from an iodine-based dip to a chlorhexidine (Hexacel) type. The cluster is dipped in a bucket of peracetic acid for 30 seconds.

"But it is working because in June our cell-count had dropped to 117,000. If a cow is over 200,000 for two out of four recordings, then we put a blue ear-tag in her, and she goes on the cull list. We're working our way down through that, where we started with the worst offenders that were over two lactations.

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We cleared out 10 cows this year, but it takes time and eliminates the possibility of voluntary recording for other issues.

"Luckily, one of the advantages of OAD is that your fertility tends to be very good - we've only 5pc empty cows, and no cows lame. That's quite impressive when you consider that this is quite a long farm with a big 400m climb from the top to the bottom," she said.